Pump unloader



H. C. I lTTLE PUMP UNLOADER Feb, 27, w23.,

Filed Feb. 25, 1922 Patente-rl hele. 27, i923.

HARRYk C. LETTLE, OE MOUNT GILEAD, OHIO, ASSGNR T THEl'Yi/DRAULIG PRESS laleltililiil Ii/l-ANUFAGTURNG COT-JAIPANY, 0F EEOUNT GLEl-LD, OI'IVIG.

PUB/IP UNLOADER.

Application filed February 23, 1922. Serial No. 538,505.

To all ifi/wm t may conce/mi.'

Be it known that I, Hanni C. Lrr'rL-n, a citizen` olthe United States, and resident of MountfGilcad, in-,the county ot lelorrow and State of Ohio, havey invented certain new and useful Improvements in Pump. Unloadersot which; the following is a: full; clear,l and exact description.

lVhen the suction check of any plunger pump is mechanically held out of its seat, the fluid which is drawn into the pump cylinderY on the snctionstroke'is ejected hack to the reservoirl by the saine passage by which it enters. n this way no delivery is securedfirom the pump. YWhenever the suction. check isal'lowed to come to rest on its seat, the delivery from the pump begins immediately.,y Ordinarily the suction check is lowered. on to its seatl at anytime the con,- trolling mechanism, permits.` This gives a satisfact-.ory actm il the check is lowered at about. the ,endet4 the suction stroke so that the loadis pichedzup by the pump ina gradualnianner. If', howeveiglthe check happens to be lowered onto its seat during the regular discharge stroke oifl the pump, the full load is often thrown upon tliepump suddenly by beginning the delivery at the point oit greatest discharge. This ottenresults in the breakage. oi' theY check7 the gears oreven the pumpY frame.

An. object of my invention is to provide inea-nsV whereby` the check is closed. only at about the end o't the suction stroke no mattei' at what pointl inthe operation the controlling mech-anisni may release the same.

Another o h'ject .is toprovide a simple and eiiicient device `for producing this result which. is controlled by the movement ofthe pump itse'li'Y through some reciprocating part thereof.

@ther (il-)jects will be apparent troni. the following deta'l'ed description and the apmended claim -'i luA the. drawings.:

' f 1 is ay side elevationparte: shown diag ...l

E rts in tical-ly.

K .onal view on a lary-rei the cheel valve held open.

a and p itin'an B mayV represent Y for giving 'a reciprocatoy y inoveinen o the puinppiston. 1 The usu. Vcross-.head 2 and shoe' are illustrated andy are normally fastened together to move tion check valve 6 cont-rolling the connec-V tion between the passageways. 7- and 8, lVhen thisvsuction check is held open, the, reciprocation of thepump piston obviously produces no delivery oi: fluid.

ln the casing 5 is niountedto reciprocate a stem 9 which has packing. l() where, it. passes through the casing. andisprovided with an enlargement il. Engaging .oneside t this enlargement is a coiled `spr g' l2 hearing at its other end against the casing 5 or` packing 10. Engaging theother side of the enlargementv lL is a larger coiled spring 13 bearing` at its other. end'v against a stem 15 guided .in a passageway 16. in a portion` 17 o't'the casing.v its clearly shown in Figure 2 there is` aU depression. ift, in. the upper end. ol: the stem 15in which thef'steni fihzis n limited amount ot' independent movement. rllhe stein l5has a gi'oo 18 there around not tar from its upper end'. i i

Adapted to engage with.this ,groovewhen the stem l5 is raised, is ai longitudinally sliding rolf l.) having a sharpend QOftofeu.- g 'fe the groove and an upti-irned end 20. at its opposite end. A. spriiig/)l is ai" anged on the rod to torce it intoeugareinent"with the groove 18 inthe stein l5 whenever 'the latter is raised. llhe uilitui'nedend 2l oft the rod Y19 is engaged by the shoe 53 ueaithe close of cach suctiony stroke ot thc puiiiipy piston. livoted at 2Q is a. lever Zhaving oneend 25 underlying the stem i5y an-'il carryil weight adjacent itsother end. Tirs lever is corniected in: any desired manner with the accuuuilator. or receiver. and as diagran'imatically illustratedl al rope or wire 2G fastened. one end to the leverz 225 runs over pulleys 27 and and supports aY weight 29 :it ils other end. which weight, is heavier This we clu 29 is suspended over the .ble part oi an accuinu tot which i onally illustreted as 'i nn ci inder Cir Al O

position shown in Figure 1, the pump will operate in its 'usual manner until the accumulator piston reaches a predetermined point, when the weights 32 will be lifted into engagement with the weight 29V and raise it. This will permit the weight 24 to fall and move the lever 23 whose end 25 will lift the stem 15. If this takes place when the pump is yon the discharge stroke the check valve will be held closed, and the upward movement of the stem 15 will compress the spring 13 after the stem 9 contacts with the check valve. W7 hen the pump plunger reaches the end of its stroke, the check valve will be free to rise, and the spring 13 will lift the stem 9 and checkvalve, placing the lighter spring 12 under compression. lThe relative movement above described between the stems 15 and 9 is permitted by the lost motion of the stem 9 in the opening 14 in the stem 15. As soon as the check valve is thus raised, the stem 15 has reached a point where the end 2O of the rod 19 can engage in the groove 18 of the stem 15 and thus prevent the stem 'from dropping. At the end of each suction stroke the sliding shoe 3 will engage the end 20 of the rod 19 and move the end 2O out of engagement with the groove, but'so long as the piston of the accumulator remains at the predetermined point, the lever 23 will hold the stem 15 up and the check valve open, and the rod 19 will immediately reengage'in the groove. i Y

Now when the pistonl of the accumulator hasbeen lowered, the weight 29 descends raising the lighter weight 2st and moving' the end 25 of the lever 23 down away from the stem 1,5. However, iff this action takes place at any vtime'except at theend of the suction stroke, the stem 15 will be retained in its upper position shown in Figure 2, holding the stem 9 in position to retain the check valve open because ot the engagement 'et the end 20 of the rod 19 with the groove 18.. Just as soon as the end olf the suction stroke is reached the cross head and shoe 3 engage the end 20 of the rod and move the end 20 out of engagement with the groove '1.8, whereupon, as the spring 13 is released, the lighter spring l2 overcomes the packing -friction and moves the stem 9 downwardly allowing the check valve 6 to close.

It is therefore apparent' that the valve can only be closed at the endv ofthe suction Y stroke irrespective of the point at which the controlling mechanism governed by the accumulatorV may function. The load there-- fore comes on the pump gradually from the beginning of the dischargestroke. n This invention has been illustrated in connection with'an accumulator in which the pressure is constant, andthe check valve is opened when the fluid discharge from the pump is 1n excess ofthe fluid drawn from the lines, in order that the accumulator n'iay not be overcharged. Itis obvious however, that it might be used in connection with devices which depend` upon an increase of pressure to open-the checkvalve. Also, the lever 23 might be used to operate by means of a spring pressed valve-similar to a pop valve, and the action of the pump would then be controlled by pressure instead of by the position ot an accumulator piston. Y Y

, The device has beenillustrated ina horizontal pump, but it is obvious that it is not limited thereto but may be used in a vertical pump. lt may also be used on a. pump-with more than one cylinder. The character of fluid placed under compression bythe pump is also immaterial. In general it may be'said that the invention is not limited except as recited in the appended claims.

l claim as my invention.

. 1. A pump unloader comprising la check valve, a receiver, meansl `for holding Vthe check valve kopen when the charge in the receiver has reached a predeterminedpoint, and means for preventing the closing of said valve except, nearvthe end of the suction stroke of the pump.

2. A pump unloader comprising a check valve a receiver, means yfor opening said check valve when the charge in the receiver has reached a predetermined point, means for retaining the check valve in open position, Vand means for releasing said retaining means only near thefend of the suction stroke of the pump.

3. A pump unloader comprising a check valve, means foropening said check valve when a predetermined charge is reached, means for retainingthe check valve inopen position while saidv charge is maintained, and means operated by a moving part of the pumpffor releasing said retaining means only near the end oi the suction stroke of the pump. t, Y

4.. A pump unloader comprising a'clieckvalve, means for opening said check yalve" when alpredetermined charge is reached, a dctent for retaining said valve in open position, and means for moving said deten't to inoperativeposition only near the end ot the suction strokeA of the pump. f

5. pump unloader comprising a check valve. means for opening the checkV valve under predetermined conditions, means for 'retaining the check valve in open position so lon as said conditions exist and means for releasing said retaining means anda-L lowing the valve to close only near the Vend I of theisuction stroke of the pump.

6. A pump unloader comprisinga checlr-.`f valve,- means for opening said check valve when -a predetermined charge is reached, a, detent for retaining the check valverin open position lexcept 4near the end of the'suction stroke of the pump, and a sliding member to engage and release the detent at that time.

7. A pump unloader comprising a. check valve, a sliding` stem for opening said valve when a predetermined charge is reached, another stern engaging the first stem, a de tent engaging the second stem to hold it in the position it reaches after it has operated the iirst stem to open the Valve, and means for releasing said detent only near the end ot the suction stroke of the pump.

S. A pump unloader comprising a check 'a-lye7 a sliding stem to engage said valve and open the same when a predetermined charge is reached, a second stem to operate the lirst stem, a detent engaging the second stern to hold it in operated position, 'and means engaged by a movingpart of the pump to release said detent only near the end of the suction stroke of the pump.

9. A pump unloader for pumps having a reciprocating part, means for causing said part to reciprocate idly, and means for causing it to resume is normal function only near the end of the suction stroke of the pump.

10. In a pumping mechanism having an accumulator and a check valve, an unloader comprising means operated by an increase ot' the charge in the accumulator above a predetermined point for opening the check valve, means for retaining the valve open so long as said condition continues, and means for thereafter releasingsaid retaining means to allow the valve to close only near the end of a suction stroke of the pump.

In testimony whereof, I have hereunto subscribed my name.

HARRY G. LITTLE. 

